Managers are open to flexible working but rarely say so when they recruit, leaving candidates "confused", according to a new report.
Recruitment firm Timewise said its research showed that the UK had not caught up with modern working practices.
A survey of 1,100 workers showed that two out of five wanted flexible work arrangements.
A separate poll of 500 managers found that just one in four vacancies they advertised in the past year included details of whether flexible working options were offered.
Nine out of 10 managers said they would be willing to talk to candidates about flexible working possibilities.
Timewise co-founder Karen Mattison said: "The world of work is changing. Flexibility is moving from niche to mainstream.
"Millions of full time workers now want some choice on where and when they work. In today's post recession market employers are having to fight harder for talent, and yet by playing their cards too close to their chests when it comes to alternative working structures, they miss a key advantage.
"Talented and skilled people are actively searching for workplaces that offer a more modern approach, where quality of performance is rated more than the pattern it took to get there."
Employment minister Jenny Willott said: "Current workplace arrangements are old-fashioned and rigid.
This is why we have extended the right to request flexible working to all employees as of 30 June.
"We have also made it easier for employers to consider requests by removing unnecessary bureaucracy.
"Extending the right to request flexible working to all employees will drive a cultural shift where flexible working becomes the norm and is not just for the benefit of parents and carers."